2/10+6/15 ,3/10+2/12,5/12+4/15 помогите

2/10  +  6/15 = 1/5  +  2/5 = (1  +  2)/5 =  3/53/10  +  2/12 = 3/10  +  1/6 = 9/30 +  5/30 =  14/30 = 7/155/12  +  4/15  = 25/60  +  16/60 =  41/60